Corsica V6-3100 3.1L MFI VIN M (1994)
Shift Solenoid: Description and Operation
Transmission Control Circuit Diagram
DESCRIPTION
The PCM controls automatic transmission shift points by use of solenoid operated fluid valves inside the transaxle. The solenoids get power when
the ignition is "ON," and become energized when the PCM completes the circuit to ground.
OPERATION
When the transmission is placed in "D" range, the PCM energizes both shift solenoids to engage first gear. The PCM constantly monitors engine
speed, vehicle speed and throttle position to determine shift points. When vehicle speed and throttle position sensor signals reach calibrated
values, the PCM turns solenoid "A" "OFF," forcing a shift to second gear (second gear - only solenoid "B" is energized). When a third gear shift is
required, the "B" solenoid is turned "OFF" (third gear - solenoids "A" and "B" are "OFF"). In fourth gear, only solenoid "A" is energized. The
PCM ignores all positions of the "PNRLDL" switch except for manual low. When the gear selector is in the manual low position, the PCM will
keep both solenoids "A" and "B" energized until the engine reaches 5,400 rpm, when the PCM will turn solenoid "A" off and force a first-second
shift. This is to avoid engine and transmission damage.
